1. Field of the Invention
The present invention relates generally to a non-volatile memory interface for use with an encryption device. More particularly, the present invention relates to a method which uses a Non-Volatile Memory circuit connected to an encryption device for storing a crypto key and an associated check word of the crypto key for use by the encryption device.
2. Description of the Prior Art
The encryption device used for encrypting data to be transmitted to a ground station via a missile's telemetry system requires a crypto key to be loaded in the encryption device to permit the encryption of the data. The standard key loaders used by the military for crypto key loading are the KOI-18 and the KYK-13. The KOI-18 is a paper type reader that serially outputs the crypto key data and clock as a series of electrical pulses. The KYK-13 is an electrical device that can store up to three crypto keys with their corresponding check word. The KYK-13 outputs data in a manner similar to the KOI-18.
The missile's telemetry system encryption device includes a Non-Volatile Memory circuit which receives the crypto key and an associated check word from the key loader. Upon receiving the crypto key and check word the Non-Volatile Memory circuit will load the encryption device with the crypto key and check word and also display the status of a load. When power is removed from the encryption device, only the Non-Volatile Memory circuit will retain the key data including the crypto key. When power is re-applied to the encryption system, the Non-Volatile Memory circuit automatically reloads the encryption device with the key data. The crypto key will remain in the Non-Volatile Memory circuit until the crypto key is erased from the circuit.
While the Non-Volatile Memory circuits used in the past perform their intended function of key data storage adequately, these circuits generally require substantially more space than is currently available on today's state of the art missile encryption systems. There is now a need to significantly reduce the size of Non-Volatile Memory circuits used with a missile's telemetry system encryption device. There is also a need to provide a method whereby a Non-Volatile Memory circuit stores a crypto key and an associated check word which is to be loaded into an encryption device allowing the encryption device to encrypt telemetry data for transmission to a ground station, a ship, an aircraft or other receiving station.